Systems and methods for monitoring the surface temperature of an object using an imager and the temperature-dependent absorption properties of semiconductors

A method for monitoring a surface temperature of at least one object, comprising:

• illuminating a semiconductor member mounted onto the surface of the object with monochromatic light, the semiconductor member having a temperature-dependent bandgap with an absorption edge that varies with temperature, wherein the semiconductor member has a back surface facing the surface of the object on which at least one image feature is located, the monochromatic light having a wavelength equal to an absorption edge wavelength that is associated with the absorption edge when the semiconductor member is at a specified temperature;
• receiving light reflected from the semiconductor member when illuminated with the monochromatic light;
• forming an image from the reflected light such that a surface temperature of the object is able to be determined from a change in visibility of the one or more imaging features in the image that is formed by the imager;
• and
• determining the surface temperature of the object from the image that is formed.

A temperature monitoring system, comprising:

• an object having a surface whose temperature is to be monitored;
• a semiconductor member mounted onto the surface of the object, the semiconductor member having a temperature-dependent bandgap with an absorption edge that varies with temperature;
• a light source configured to illuminate the semiconductor member with monochromatic light having a wavelength equal to an absorption edge wavelength that is associated with the absorption edge when the semiconductor member is at a specified temperature;
• and
• a detector configured to receive light reflected from the semiconductor member when illuminated with the monochromatic light such that a surface temperature of the object is at the specified temperature when a change in an amount of reflected light that is received indicates that the wavelength of the monochromatic light is equal to the absorption edge wavelength at the specified temperature;
• an optical fiber having a first end through which the monochromatic light exits and the reflected light from the semiconductor member is received, the first end of the optical fiber being spaced apart from the semiconductor member by a first gap over which the monochromatic light travels to illuminate the semiconductor member, the optical fiber having a second end with a facet extending at a non-perpendicular angle with respect to an optical axis of the optical fiber, the light source and the detector being laterally offset with respect to the optical axis of the optical fiber such that the monochromatic light from the light source is directed into the optical fiber through the facet toward the optical axis and the reflected light from the semiconductor member is directed toward and received by the detector after exiting the facet.